/**
* @Title: TextWebSocketFrameHandler.java
* @Package com.cenntro.common
* @Description: 
* @author Administrator
* @date 2019年7月25日
* @version V1.0
*/
package com.cenntro.common.websocket;

import static io.netty.handler.codec.http.HttpUtil.isKeepAlive;

import java.util.Date;

import org.apache.tomcat.jni.Time;
import org.slf4j.LoggerFactory;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.handler.codec.http.websocketx.CloseWebSocketFrame;
import io.netty.handler.codec.http.websocketx.PingWebSocketFrame;
import io.netty.handler.codec.http.websocketx.PongWebSocketFrame;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketServerHandshaker;
import io.netty.handler.codec.http.websocketx.WebSocketServerHandshakerFactory;
import io.netty.util.CharsetUtil;
import lombok.extern.slf4j.Slf4j;

/**
* @ClassName: TextWebSocketFrameHandler
* @Description: TODO
* @author Administrator
* @date 2019年7月25日
*
*/
@Slf4j
public class TextWebSocketFrameHandler extends SimpleChannelInboundHandler<Object> {

    private final org.slf4j.Logger logger = LoggerFactory.getLogger(this.getClass());

    private WebSocketServerHandshaker handshaker;

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
        if (msg instanceof FullHttpRequest) { // 以http请求形式接入，但是走的是websocket
            handleHttpRequest(ctx, (FullHttpRequest) msg);
        } else if (msg instanceof WebSocketFrame) { // 处理websocket客户端的消息
            handlerWebSocketFrame(ctx, (WebSocketFrame) msg);
        }
    }
    

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        // 添加连接
        logger.debug("客户端加入连接：" + ctx.channel().id());
        //ChannelSupervise.addChannel(ctx.channel());
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        // 断开连接
        logger.debug("客户端断开连接：", ctx.channel().id());
        ChannelSupervise.removeChannel(ctx.channel());
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }

    private void handlerWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame) {
        // 判断是否关闭链路的指令
        if (frame instanceof CloseWebSocketFrame) {
            handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain());
            return;
        }
        // 判断是否ping消息
        if (frame instanceof PingWebSocketFrame) {
            ctx.channel().write(new PongWebSocketFrame(frame.content().retain()));
            return;
        }
        // 本例程仅支持文本消息，不支持二进制消息
        if (!(frame instanceof TextWebSocketFrame)) {
            logger.debug("本例程仅支持文本消息，不支持二进制消息");
            throw new UnsupportedOperationException(
                    String.format("%s frame types not supported", frame.getClass().getName()));
        }
        // 返回应答消息
        String request = ((TextWebSocketFrame) frame).text();
        log.info("服务端收到：" + request);
    }

    /**
     * 唯一的一次http请求，用于创建websocket
     * */
    private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) {
        // 要求Upgrade为websocket，过滤掉get/Post
        if (!req.decoderResult().isSuccess() || (!"websocket".equals(req.headers().get("Upgrade")))) {
            // 若不是websocket方式，则创建BAD_REQUEST的req，返回给客户端
            sendHttpResponse(ctx, req,
                    new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST));
            return;
        }
        log.info("开始握手： {}", req);
        WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory("ws://localhost:8080/websocket", null, false);
        handshaker = wsFactory.newHandshaker(req);
        if (handshaker == null) {
            WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());
        } else {
            ChannelFuture cf =  handshaker.handshake(ctx.channel(), req);
            String url = req.uri();
            log.info("握手的url = {}", url);
            ChannelSupervise.addChannel(cf.channel(), url.replace("/ws/", ""));
        }
    }

    /**
     * 拒绝不合法的请求，并返回错误信息
     * */
    private static void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest req, DefaultFullHttpResponse res) {
        // 返回应答给客户端
        if (res.status().code() != 200) {
            ByteBuf buf = Unpooled.copiedBuffer(res.status().toString(), CharsetUtil.UTF_8);
            res.content().writeBytes(buf);
            buf.release();
        }
        ChannelFuture f = ctx.channel().writeAndFlush(res);
        // 如果是非Keep-Alive，关闭连接
        if (!isKeepAlive(req) || res.status().code() != 200) {
            f.addListener(ChannelFutureListener.CLOSE);
        }
    }
}
